Electromagnetic relays



1957 J. L. SLONNEGER 2,804,519

ELECTROMAGNETIC RELAYS Filed Jan. a, 1956 INVENTOR. L/OH/V Z 5L ONNE GER BY HIS ATTORNEY United States ELECTROMAGNETIC RELAYS John L. Slonneger, Morrison, 11]., assignor to General Electric Company, a corporation of New York Application January 3, 1956, Serial No. 558,000

Claims. (Cl. 20087) My invention relates to small electromagnetic relays and more particularly to electromagnetic relays used in circuits for energizing small single-phase motors.

Electromagnetic relays suitable for use with fractional horsepower single-phase motors generally comprise an insulating housing containing an electromagnetic coil for actuating an armature to move the relay contacts between open and closed positions in response to alternating current flowing through the coil. The insulating housing is generally formed of two members, riveted or bolted together which enclose the various operating components of the relay. The terminals for the coil and contacts are usually screwed or fastened down to the housing.

An object of the invention is to provide an inexpensive electromagnetic relay in which all of its component parts including the housing and terminals may be assembled and held together by the arrangement thereof without further fastening means.

Another object is to provide an inexpensive current relay having means for easily compensating for minor variations due to manufacturing tolerances so that the relay may be accurately calibrated to have the proper pick-up characteristic after assembly.

In general, in accord with the invention an insulating housing is provided containing the magnetic armature and contact assembly for the relay. An electric coil surrounds the housing and functions to move the magnetic armature assembly from contact open to closed position in response to energization of the coil. The housing is split into two parts along a plane passing axially through the coil and the coil itself serves to hold these two parts of the housing together against disengagement.

In accord with another feature of the invention, terminal members extend external to one side of the housing above and'below the electric coil and a side cover member constituting one of the two parts of the housing serves to trap and secure the terminal members within the base portion of the housing. As mentioned above, the base and side cover portions of the housing are held together against disengagement by the electric coil.

In accord with a further feature, the invention includes a cylindrical armature slidable on a sleeve against the force of a spring which bears against a cap whose position on said sleeve may be easily adjusted during manufacture to compensate for variations in pick-up characteristic among such relays when mass produced.

The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, together with further objects and advantages thereof may best be understood by referring to the following description taken in connection with the accompanying drawing in which Figure 1 is a front view of an electromagnetic relay embodying the invention, 7

I Figure 2 is a side cross-sectional view taken through the center of the relay of Figure l, and

2,804,519 Patented Aug. 27, 1957 Figure 3 is an exploded perspective view of the component parts of the relay of Figure 1.

Referring to the drawing, the invention is shown in one form embodied in a relay 10 of a calibrated current type used in split-phase starting of fractional horsepower motors. Relay 10 comprises a two-part insulating housing 11 including an open-sided base member 12 and a flat side-covering member 13. The two-part housing 11 may thus be considered to be split along a vertical plane. Housing 11 has an inverted T-shaped portion 14 defining a horizontal chamber 15 and a vertical chamber 16 communicating with chamber 15.

A movable armature and contact-bridging assembly 17 is slidably supported on a vertical shaft 18 within chambers 15 and 16. The moving parts of assembly 17 include a cylindrical-insulating sleeve 19 axially slidable on shaft 18, a cylindrical magnetic-armature member 20 vertically slidable on sleeve 19 and a contactbridging member 21 extending below armature member 20 within horizontal chamber 15. A metal cap 22 is rigidly fastened, such as by crimping, around sleeve 19 above armature 20 and resilient means, such as a light spring 23 surrounding sleeve 19 between armature 20 and cap 22, is provided for resiliently transmitting movement of armature 20 to slidable sleeve 19 so that armature 20 can vibrate under the influence of alternating excitation without chattering the contacts.

Movable assembly 17 is securely supported in proper position within base member 12 of housing 11 by engagement and trapping of the opposite end portions 24 and 25 of shaft 18 within and against the inner walls defining suitable top and bottom recesses for receiving these end portions 24, 25 of shaft 18. The recess for accommodating the lower end portion 25 of shaft 18 is a small double-shouldered cavity 26, best seen in Figure 2, whiie the upper recess for receiving end portion 24 of shaft 13 is a narrow rectangular passageway 27 opening into the larger vertical chamber 16. End portion 24 of shaft 18 is bent forward to prevent rotation of the shaft by the side walls defining recess 27 and to prevent forward motion of shaft 18 by the engagement of the end of portion 24 against the inner surface of side-covering plate 13.

Contact-bridging member 21 is a conductive metal strip loosely and slidably mounted on insulating sleeve 19 by insertion of sleeve 19 through a hole 28 in the center of bridging member 21. A collar 29 on the bottom of insulating sleeve 19 acts as a lower stop for the bridging member 21. Armature member 20 normally rests when in an unenergized condition on bridging member 21 but is free to move upwardly away from the bridging member on insulating sleeve 19 against the force of spring 23. Contact-bridging member 21 carries moving contacts 30 at opposite ends which upon elevation of the bridging member 21 engage stationary contacts 31 carried by terminal members 32. These terminal members 32 comprise an elongated strip of conductive metal having an internal rectangular portion 32a which carries the stationary contact 31 and an external connecting portion 32b preferably angularly offset relative to the plane of internal portion 32a to facilitate connection to this external portion 32b. The opposing side edges 33 of the internal rectangular portion 32a of terminal member 32 fit snugly within channels 34 provided within the base member 12 of the insulated housing 11. Shouldered or cutout portions such as notches 35 are formed in the sides of terminals 32 immediately above the internal portion 32a to receive the side-edge portions 36 on the stem 37 of T-shaped cover member 13. The inter-engagement of these side portions 36 of cover 13 within notches 35 serves to trap the terminal members 32 within housing 11 against any a 3 forces tending to pull these terminal members forwardly out of the relay.

A coil-connecting terminal member 38 is located centrally in the upper portion of relay 1th with its side edges 38a snugly fit within suitable opposing channels 39 in the upper portion of base member 12 of insulated housing 11. A horizontal portion 40 of coil-connecting terminal 33 has a shouldered or cut-out portion such as a window 41 formed therein for receiving the upper-end portion 4-2 of side-covering member 13 such that the terminal 38 is trapped against forward movement by this inter-engagement. A vertical portion 43 of terminal member 38 has a tapped hole 43a for receiving a connection retaining screw (not shown). The central upper portion of insulating base member 12 is formed into an upstanding three-sided wall defining a cavity 44 immediately forward of narrow cavity27 for receiving such connecting screw.

The upper portion of insulating base 12 also has side extension portions 55 each containing cylindrical holes 46 therethrough for receiving mounting screws for the relay. Upper side-extension portions 45 of insulated base 12 together with the lower side-extension portions 47 of the base member 112 and the connecting central portion 48 thereof form a bobbin for accommodating an electric coil 50. Coil 5-9 is wound around the central portion 48 between the upperand lower-side extension portions 45 and 47 of the housing 11 and serves to trap or lock the side covering member 13 beneath the coil 59 and thus to hold the two parts of the housing together. One end of the coil 59 is connected to coil-connecting terminal 38 and the other end 52 of coil 50 is connected to one of the contact-carrying terminal members 32. Since the coil 5%) is normally formed of insulated wire no further insulation thereof is required.

In the assembly of relay it) the contact-carrying terminals 32, and the armature and contact-bridging assembly 17 are dropped within their accommodating recesses in the insulating base member 12, the coil-connecting terminal 38 is then inserted within channels 39 and the side-cover ing member 13 inserted by vertical upward motion between notches 35 of the contact-carrying terminals 32 and through window 431 of the coilconnecting terminal 38. The coil-covering member 13 is then pressed backward until it is a snug fit within the walls of the base member 12. Coil St) is then wound around the insulating housing 11 and the leads 51, 52 connected to their proper terminals. It will be appreciated that the cover member 13 is held against vertical movement by its snug fit within the side walls of base member 12 and trapped against forward horizontal movement by coil 50.

In operation, when starting a motor an electric current in coil 50 produces a magnetic field which elevates magnetic armature 20 on insulating sleeve 19 against the force of spring 23. The elevation of armature N is transmitted by spring 23 against cap 22 which in turn causes the elevation of sleeve 1? on shaft 18. As sleeve 19 moves upwardly it carries contact-bridging member 21 on collar 29 until movable contacts 30 engage the stationary contact 31 on the terminal members 32, thereby making connection between conductors connected to these contact-carrying terminals 32. It will be appreciated that adjustment of the vertical position of cap 22 on sleeve 19 during manufacture permits control over the point that contacts 30, 31 engage during elevation of armature 20 such that the magnetomotive force required to elevate each armature to its contact closing position can be made identical despite minor variation in the size and location of the armature and contact assembly 17. Further elevation of magnetic armature 2i) beyond its contact-kissing position increases the contact force transmitted to the contact bridging member through spring 25, cap 22 and slidable-insulating sleeve 19. Spring 23 also prevents vibrations in the energized armature from being transmitted to the contacts. The maximum elevation of magnetic armature 20 is limited by a shoulder 53 in the insulated-housing portion defining the upper end of vertical chamber 16.

When the motor comes up to speed the current in coil 59 drops, and this in turn causes the armature 20 to drop immediately and to strike a hammer blow upon the upper surface of contact-bridging member 21. It will be appreciated that this hammer blow is desirable in order to break any welding which might occur at the contacts.

Although I have described above a specific embodiment of the invention many modifications may be made and I intend by the appended claims to cover all such modifications as fall within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electromagnetic relay comprising an insulating housing including a recessed base member having an open side and a cover member for closing said side, relatively movable contacts and a magnetic armature operable to close said contacts located within recesses in said base member and trapped therein by said cover member, and an electric coil for energizing said armature surrounding said housing and holding said base and cover member against disengagement.

2. An electromagnetic relay comprising an insulating housing havin a T-shaped portion defining a horizontal chamber and a communicating-vertical chamber, a coil surrounding the vertical-chamber portion of said housing, a contact assembly within said horizontal chamber, and a magnetic armature within said vertical chamber for actuating said contact assembly in response to a magnetic field from said coil, said housing being formed of two parts split along a plane axially cutting said coil, said parts being held together by said coil.

3. An electromagnetic relay comprising an insulating housing having an inverted T-shaped portion defining a horizontal chamber and a vertical chamber extending upwardly from the center of the horizontal chamber, a coil surrounding the vertical-chamber portion of said housing, a vertically movable insulating sleeve extending axially Within said vertical chamber into said horizontal chamber, stationary contacts in the ends of said horizontal chamber, a conductive bridging member supported at its center on said sleeve within said horizontal chamber and having contacts at opposite ends for engaging said stationary contacts upon vertical movement, a magnetic armature surrounding and slidable on said sleeve and energizable by said coil to move between a position resting on said bridging member and an elevated position, and resilient means for transmitting motion between said armature and sleeve, said housing being formed of two parts split along the plane axially cutting said coil and being held against disengagement by said coil.

4. An electromagnetic relay comprising an insulating housing including a base member having a plurality of recesses opening through one side thereof for receiving the parts of said relay and a fiat-cover member for closing the front of said recesses, a terminal for said relay having a portion extending within said base member and a portion extending external through the front thereof, said terminal having a shouldered portion between said internal and external portion within the shoulders of which said cover member is interfitted thereby to trap said terminal within said housing, and a coil for energizing said relay surrounding said housing and locking said cover member on said base.

5. The electromagnetic relay of claim 4 wherein the shouldered portion of said terminal comprises a notch in the side thereof.

6. The electromagnetic relay of claim 4 wherein the shouldered portion of said terminal comprises a rectangular window therethrough.

7. An electromagnetic relay comprising an insulating housing including a base member having a plurality of recesses opening through one side thereof for accommodating parts of said relay and a side covering member for closing said recesses and trapping said parts therein, and a coil for energizing said relay surrounding said housing and holding said base and cover member against disengagement.

8. The electromagnetic relay of claim 7 wherein some of the parts of said relay have portions internal and external to said housing, said latter parts having shouldered portions between said internal and external portions within the shoulders of which said cover member is interfitted.

9. The electromagnetic relay of claim 7 wherein the housing has a central portion of reduced cross section between upper and lower side extension portions, whereby said housing forms a bobbin for said coil wound around said central section.

10. An electromagnetic relay comprising an insulating housing having an inverted T-shaped portion defining a horizontal chamber and a vertical chamber extending upwardly from the center of the horizontal chamber, a coil surrounding the vertical chamber portion of the housing,

a vertically movable insulating sleeve extending axially within said vertical chamber into said horizontal chamber, stationary contacts at the ends of said horizontal chamber, a conductive bridging member supported at its center on said sleeve within said horizontal chamber and having contacts at opposite ends for engaging said stationary contacts upon vertical movement, a magnetic armature slidable on said sleeve and energizable by said coil to move between a position resting on said bridging member and an elevated position, a cap member crimped to said sleeve above said armature, and a spring between said armature and cap member for resiliently transmitting motion between said armature and sleeve, the location of said cap member determining in part the pick-up characteristic of said bridging member.

References Cited in the file of this patent UNITED STATES PATENTS 

